Asthma self?management is essential for preventing exacerbations and reducing the burden of the disease. However, poor adherence to prescribed treatment and poor recognition of symptoms leads to reduced asthma control, particularly among adolescents. Studies show that adolescents lack understanding about self?management, and that asthma education during clinic visits is deficient, resulting in insufficient asthma management. Mobile technology, specifically, mobile applications (or apps) are an efficient way to increase patient?provider communication, provide feedback on asthma management, and deliver asthma education. Our pilot work has demonstrated that an app can be effective at improving asthma control in adolescents aged 12?17, and that adolescents are enthusiastic about utilizing mHealth technologies for asthma management, but that existing apps are not engaging or appealing enough to an adolescent population to sustain long?term use. For this pilot study, we will test the feasibility, acceptability, and adherence to a smartphone app for asthma self?management in order to obtain data necessary to complete a future large efficacy trial of the app in adolescents with persistent asthma. The objective of this project is to use an agile, iterative, user?centered design process to tailor our existing proof of concept app to adolescent user preferences and to use a mixed? methods approach to test feasibility, acceptability, adherence, and preliminary efficacy. The long?term goal is to identify mHealth technological approaches that facilitate self?management of chronic diseases, particularly among adolescents, and to develop marketing strategies to promote long?term support of these approaches. The rationale for this project is that adolescents are quick to adopt mobile technologies, have a high degree of smartphone use, and are at a point of transition from parental management of their chronic condition to self? management, making this a priority population for the development of interventions targeting asthma control. For this project, we have two specific aims: 1) To refine an asthma self?management app for adolescents with persistent asthma; and 2) To assess feasibility, acceptability, and adherence to the app in a small randomized controlled trial. The approach is innovative because we are incorporating a user?centered design process to integrate multiple components for facilitating asthma self?management in a mHealth tool tailored for adolescents within the Technology Acceptance Model framework. Despite studies showing that mHealth tools can be effective, few have prioritized an adolescent audience or evaluated the tool compared to standard of care using rigorous, mixed?method approaches. This research is significant because asthma is the most common chronic disease of childhood in the US and the prevalence of the condition continues to rise, and so innovative tools to improve self?management of the disease are critically needed.